(a) Field of the Invention
The present invention relates to a printing apparatus and method for measuring and compensating for a synchronization error.
A lithography technology has been widely used in a technology of manufacturing electronic devices according to the related art. However, in performing an actual process using the lithography technology, various and complicated detailed processes, such as vacuum deposition, exposure, developing, plating, and etching, are required, which leads to a problem in that a process design and an apparatus configuration may be complicated, and the like. Further, due to the development of a micro technology in various fields, a method for manufacturing an integrated circuit using other technologies other than using the photo lithography technology has been sought.
Electronic printing is a technology of manufacturing electronic devices by simply performing a printing process. Since the electronic printing may basically remove process complexity involved in the photo lithography process by replacing the foregoing photo lithography process, research into the electronic printing having applications expanded to various fields, and the like, has been actively conducted recently. As the recently available printing technology, there are a contactless type printing technology and a contact type printing technology. A representative example of the contactless type printing technology may include inkjet, spray, slot die coating, and the like and a representative example of the contact type printing technology may include gravure, gravure offset, reverse offset, screen printing, and the like.
Meanwhile, in a recent technology of manufacturing a semiconductor, a case in which a film type substrate of a flexible material, not a substrate of a hard material, is used has increased. In the case of using the film type substrate, a process speed is increased, and thus mass production may be achieved. In this case, since production efficiency may be increased when a roll-to-roll production method is combined with the electronic printing technology as described above, a study of a combination of the roll-to-roll production method and the electronic printing technology has been very actively conducted.
The contactless type printing technology is appropriate to perform printing based on a type of uniformly coating a wide area. However, in order to form a fine pattern, the contact type printing technology, such as gravure and reverse offset, is mainly used. In the contact type printing technology, a roll is frequently used to perform a continuous process. That is, patterns to be printed are formed on the roll and the patterns on the roll are transferred to the substrate, thereby performing the printing. The contact type printing technology may be applied to both of the substrate of a hard material and the substrate of a flexible material. In the case of the substrate of a hard material, the roll contacts the substrate disposed on a stage and in the case of the substrate of a flexible material, the roll contacts another roll or contacts the flexible substrate which is supported by another flat type support part. Except for the substrate, in the former case, it is considered that the roll may contact the stage and in the latter case, it is considered that the roll may contact the roll or the roll may contact the flat type support part.
(b) Description of the Related Art
In the contact type electronic printing using the roll, a rotating velocity of the roll needs to be well synchronized with a movement velocity of the substrate support part supporting the substrate. When the synchronization is not properly made, problems, such as sliding of the roll, occur, such that the patterns may not be correctly printed on the substrate.
In order to synchronize the rotating velocity of the roll with the movement velocity of the substrate support part, a product of a radius of the roll and an rotating angular velocity of the roll needs to be the same as a linear movement velocity of the substrate support part. However, the radius of the roll is changed since a surface of the roll is actually made of a flexible material, such as rubber, and the printing job is performed while the roll applies printing pressure to the substrate, that is, the roll is pressed at the printed position. Therefore, even though the product of the radius of the roll which is not deformed and the rotating angular velocity of the roll is equal to the linear movement velocity of the substrate support part, the synchronization error between the roll and the substrate occurs due to the change in the radius of the roll at the time of the actual printing job.
Various technologies for compensating for an error in the contact type printing according to the related art are disclosed. Korean Patent No. 0981278 (“Printing apparatus of flexible electronic devices available for alignment error compensation on roll and board and printing method thereof”, Sep. 3, 2010), Japanese Patent Laid-Open Publication No. 2011-173393 (“Printing roll and plate, apparatus for compensating for tilt of print”, Sep. 8, 2011), Japanese Patent Laid-Open Publication No. 2011-037239 (“Method and apparatus for compensating for error at printed position”, Feb. 24, 2011), and the like, disclose a technology of compensating for various errors to align printed positions, but may never compensate for the synchronization error between the roll and the substrate support part as described above. Japanese Patent Laid-Open Publication No. 2004-058536 (“Synchronous compensation apparatus”, Feb. 26, 2004) discloses a technology of compensating for error occurring due to sliding between the roll and the substrate and is to control a rotation of a holder, and the like by detecting whether running paper is correctly transferred in a rotary press by a leading edge detector, but does not have a solution of a synchronization error problem between the roll and the substrate support part as described above by never considering the case in which the radius of the roll is changed.
As such, the related art does not have a solution of compensating for the synchronization error between the roll and the substrate support part occurring due to a deformation, and the like, which is caused by the printing pressure of the roll at the time of the electronic printing, thereby greatly limiting the improvement in printing precision.